medwireNews: Patients with osteoarthritis (OA) in the knee and hip, but not the hand, have an increased risk for venous thromboembolism (VTE), which may be exacerbated by knee and hip replacements, researchers report.
The findings are based on a review of medical records from the UK THIN database of 20,696 patients with knee OA, 10,411 with hip OA, and 6329 with hand OA who were each matched – on characteristics including age, sex, and BMI – to up to five individuals without OA.
Over nearly 6 years of mean follow-up, 327 and 201 VTE events (pulmonary embolism or deep vein thrombosis) occurred in patients with knee and hip OA, respectively, equating to an incidence rate of 2.7 and 3.3 events per 1000 person–years. This was significantly higher than the corresponding 2.0 and 1.8 events per 1000 person–years among the matched non-OA individuals.
After adjusting for additional variables, including smoking status, comorbidities, and alcohol consumption, patients with knee and hip OA were a significant 38% and 83% more likely to experience a VTE event than those without OA.
But patients with hand OA were no more likely to have a VTE event than their matched non-OA counterparts, with incidence rates of 1.5 and 1.6 events per 1000 person–years, respectively.
Writing in the Annals of the Rheumatic Diseases, Guanghua Lei (Central South University, Changsha, China) and co-authors explain that “immobility and surgery, including knee or hip replacement, are the two major risk factors for VTE,” and these joint replacement surgeries were a respective 10- and 20-fold more common among knee and hip OA patients than matched individuals without OA.
Patients who had a knee or hip replacement were significantly more likely to experience a VTE within 6 months of surgery than those who had neither surgery, at respective rates of 15.8% and 14.9% versus 1.2% and 1.2%, and corresponding hazard ratios (HRs) of 1.07 and 1.14.
The researchers therefore estimate that knee and hip replacements accounted for 24.8% and 28.1% of the association between knee and hip OA and VTE, leading them to suggest that “knee and hip replacement surgery indeed played an important role in the association.”
Overall, this lends “credibility to our observations that the increased risk of VTE was only among patients with knee or hip OA, but not hand OA,” they say.
The team also investigated the effect of other major surgeries on the risk for VTE among knee and hip OA patients, but found no significant associations.
Lei et al propose: “Clinicians managing patients with knee or hip OA, especially those with movement limitations, could then have a high index of suspicion for VTE, particularly in the presence of non-specific symptoms and signs.”
And they conclude that “strategies aimed at encouraging patients with knee or hip OA to actively participate in physical activities seem justified.”
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Ann Rheum Dis 2020; doi:10.1136/annrheumdis-2020-217782